System and method for distributing information via a communication network

ABSTRACT

A communication system for distributing information via a network to one or more subscribers includes a multi-port switch, one or more radio frequency (RF) modems coupled to respective ports of the switch, a combiner and a transmitter. The switch forwards source information to the RF modems based on address information. Each RF modem modulates and up converts information from the switch to an RF signal within a respective subscriber channel of the television broadcast spectrum. Each channel is assigned to one or more subscribers, and each subscriber is allocated unshared bandwidth. Each channel may be further divided into unshared bandwidth increments, so that multiple subscribers may share a single channel. The combiner combines modulated information from each RF modem into a combined signal and the transmitter transmits the combined signal to the subscribers via the network. An HFC network including a distribution point and one or more optical nodes is contemplated, each optical node serving a particular geographic area via a corresponding coaxial cable. Each subscriber destination includes a gateway device or the like that is tuned to a corresponding channel to retrieve source information from that channel, and to deliver the information to one or more local subscriber devices. The gateway further includes converters, a modulator and an up converter to receive and transmit subscriber information upstream to the distribution point. The gateways and an address resolution server enforce point to point communications. A bandwidth manager allocates bandwidth and monitors bandwidth usage.

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] The present application is based on U.S. Provisional Applicationentitled “Switched Ethernet Communication network Utilizing Hybrid FiberCoax Delivery Plant”, Application No. 60/184,362 filed Feb. 23, 2000,which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to information delivery anddistribution, and more particularly, to a system and method forallocating unshared, bidirectional and deterministic bandwidth tosubscribers in a network.

DESCRIPTION OF RELATED ART

[0003] The demand for broadband content by business and residentialsubscribers is continually increasing. Broadband content includesmultiple types of entertainment programming, communications and data,such as broadcast television channels, video on demand, streaming video,multimedia data, internet access, voice-over-IP, etc. To meet theincreasing demand, it is necessary to increase bandwidth to eachsubscriber and to improve quality of service. Current deliverytechnologies include (1) several variations of DSL (digital subscriberline) technology, such as ADSL (asymmetrical DSL) and the like, whichuses telephony technology, and (2) cable modem systems using televisiontechnology and HFC (hybrid fiber coax) distribution networks. Theexisting legacy technology for providing broadband content is becomingincreasingly inadequate to meet the demand.

[0004] DSL technology is a method of delivering data over a twisted pairof copper wires or twisted pair cables, and typically uses the PublicSwitched Telephone Networks (PSTN). There are several major problemswith provisioning video services over the existing PSTN and twisted paircables (network plant). The existing network plant is not uniform andmost of the plant is old with poor copper conditions that causes signalloss and line noise. In fact, ADSL cannot be provisioned for a largeportion of the population over the existing plant because of significantdistances to the closest switch and poor conditions of the existingplants. In addition, ADSL currently has a limited downstream bandwidth,and inherently provides a very limited return bandwidth. ADSL is notadequate for many types of content originating at a subscriberdestination, such as video conferencing and the like because of itsbandwidth limitations and characteristics.

[0005] Cable modem systems utilize the television broadcast spectrum andtelevision technology to broadcast so-called broadband data tosubscribers. One problem with delivery of broadband data (video ondemand, streaming video, etc.) using existing HFC networks is thelimitation on available delivery spectrum. The television data deliverysystems have been established to deliver data to subscribers over atelevision broadcast spectrum extending from approximately 15 Megahertz(MHz) to approximately 860 MHz. Delivery of analog television downstreamto the subscriber occupies the spectrum between approximately 54 MHz to550 MHz, which leaves a relatively small range of spectrum for thedelivery of digital data over HFC cable modem systems. The diplex filterseparating the downstream from the upstream is currently located in theexisting cable plant within the frequency range of approximately 42 to54 MHz. Therefore, the two effective delivery frequency ranges usinglegacy HFC systems are those between approximately 15-42 MHz (upstream)and those between approximately 550-860 MHz (downstream).

[0006] Existing HFC cable networks are based on the Cable ModemTermination System (CTMS) and the Data-Over-Cable Service InterfaceSpecifications (DOCSIS). These legacy systems use a shared frequencychannel to broadcast all data to every downstream subscriber. The sharedchannel is generally 6 MHz wide providing a total data bandwidth ofapproximately 27-38 Mbps for digital information. The channel, however,is shared among many subscribers, so that the data rate variesdramatically depending upon the time of use and the number ofsubscribers simultaneously logged on. The quality of service isparticularly low during popular usage time periods. An exemplary legacysystem might distribute the shared channel among 4 separate nodes, eachserving approximately 500 subscribers or more, so that resultingdownstream data rate is often relatively low. The upstream sharedchannel is usually smaller, such as 3.2 MHz or less, and a “poll andgrant” system is employed to identify data for upstream transmission.The resulting upstream performance is often no higher (and sometimesless) than a standard 56 Kbps modem.

[0007] It is desired to provide a system and method for distributinginformation via existing and future communication networks that meetsthe increasing demand for broadband content.

SUMMARY OF THE INVENTION

[0008] A communication system for distributing information via a networkto subscriber destinations according to an embodiment of the presentinvention includes a multi-port switch, one or more radio frequency (RF)modems coupled to respective ports of the switch, a combiner and atransmitter. The switch forwards source information for the subscriberdestinations to the RF modems based on address information. Each RFmodem operates to modulate and up convert information received from theswitch for corresponding subscriber destinations to an RF signal withina respective subscriber channel of a television broadcast spectrum. Eachsubscriber channel is assigned to one or more of the subscriberdestinations, and each subscriber destination is provided with anunshared bandwidth allocation. The combiner combines modulatedinformation from each RF modem into a combined signal and thetransmitter transmits the combined signal to the subscriber destinationsvia the network. Each subscriber destination includes a gateway deviceor the like that is tuned to a corresponding subscriber channel toretrieve source information from that channel. A significant benefit ofthe present invention is that each subscriber may be allocated anunshared, deterministic and bidirectional bandwidth.

[0009] The originator of the source information depends upon theparticular network configuration. A point of distribution, such as adistribution hub or the like, is contemplated, which may be a headend oran originator of content including satellite receivers and associatedequipment and the like, or which may be a communication or distributionhub coupled downstream from a headend facility. In this manner, one ormore distribution points each serve a relatively large geographic area.The point of distribution may include one or more source servers coupledto the switch that provide content or source information for thesubscriber destinations. The source servers may include, for example, avideo server, a computer network server, a telephone network server, autility server, etc., depending upon the desired services and content tobe provided to the subscriber destinations. The source servers may alsoinclude an MPEG converter that provides converted broadcast videocontent to the subscriber destinations.

[0010] The source information may be implemented into any one of manydifferent formats. For example, the source information may be in theform of fixed- or variable-sized packets, frames, or cells, each havingaddress information indicative of an intended destination. The switchretrieves address information from the packets and forwards the packetsbased on the address information. The format of the source informationmay also depend upon the type of switch. For example, the switch may bean Ethernet switch operating at 100 megabits per second (Mbps), or agigabit Ethernet switch operating at one gigabit per second (Gbps).Other types of switches are contemplated, such as an AsynchronousTransfer Mode (ATM) network switch operating with fixed-size cells.

[0011] The switch may also be implemented as a matrix of switches. Inone embodiment, for example, the switch includes a switch matrix witharrays of switches organized as a pyramid configuration. The switchmatrix includes a lowest level first array of switches and one or morehigher level arrays of switches. Each first array switch is coupled to asubset of the RF modems, and each switch of each higher level array iscoupled to a subset of switches of an adjacent lower level array. Thefirst, lowest level array handles a relatively high level of bandwidth,a second array handles a medium level of bandwidth, and a third arrayhandles a relatively low level of bandwidth. In a particular embodiment,the third array interfaces a telephone network server for handlingtelephonic data, the second array interfaces a computer network serverand handles telephonic and computer network data, and the third arrayinterfaces a video server and handles video, telephonic and computernetwork data. The switch matrix may be configured to operatesignificantly below its maximum bandwidth capacity to providestatistically starved capability. The switch matrix may further includea manager switch for handling management functions and subscriber tosubscriber traffic. A bandwidth manager and/or address resolution servermay be provided and coupled to the manager switch. The bandwidth mangerallocates, monitors and tracks bandwidth usage. The address resolutionserver, in cooperation with gateway devices, enforces point to pointtype traffic in the network.

[0012] The network may include an optical plant, where the transmitterincludes an optical transmitter that converts a combined electricalsignal to an optical signal and that transmits the optical signal ontothe optical plant. For upstream communications, an optical receiver isprovided that that converts an optical upstream signal with subscriberinformation to a subscriber electrical signal. A splitter provides thesubscriber electrical signal to one or more tuners, where each tunerextracts a corresponding subscriber RF signal. Also, one or moredemodulators are provided, where each demodulator demodulates subscriberinformation from a corresponding subscriber RF signal and forwards thesubscriber information to the switch.

[0013] The subscriber channels may extend over almost the entire portionof the television broadcast spectrum, which is an embodiment directedtowards business applications or the like. In this case, the entiretelevision broadcast spectrum is divided into an upstream portion and adownstream portion. Mid split or high split embodiments arecontemplated, for example, in which the diplex filter is located at ahigher frequency range to provide a more symmetric system with roughlyequivalent down and up stream portions. Each subscriber channel includesa downstream subscriber channel in the downstream portion and anupstream subscriber channel in the upstream portion.

[0014] Alternatively, a broadcast television source is included whichprovides broadcast television information in a predetermined frequencyrange of the television broadcast spectrum, such as the frequency range54-550 MHz or the like. In this case, the subscriber channels areallocated into a remaining portion of the television broadcast spectrumoutside the frequency range allocated for broadcast televisioninformation. In a particular embodiment, for example, the subscriberchannels include a downstream portion above the broadcast televisionfrequency range and an upstream portion below the broadcast televisionfrequency range. The combiner receives and combines the broadcasttelevision information into the combined signal along with thesubscriber channel information. Also, a video on demand (VOD) andmodulator server may be provided that provides video information, wherethe combiner receives and combines the video information from the VODand modulator server into the combined signal.

[0015] A bandwidth manager may be provided to allocate unsharedbandwidth to each subscriber destination. Although an entire subscriberchannel may be allocated to one subscriber, each subscriber channel mayfurther be subdivided into multiple bandwidth increments. In aparticular embodiment, for example, each subscriber channel hasapproximately 40 Mbps capacity, which is further divided into 5 Mbpsunshared increments.

[0016] Each subscriber destination, therefore, may be allocated anymultiple of 5 Mbps downstream bandwidth up to 40 Mbps for a givensubscriber channel. In this manner, multiple subscriber destinations maybe assigned to one subscriber channel. A static system is contemplatedin which each subscriber destination is allocated a fixed amount ofunshared bandwidth. Alternatively, a dynamic system is contemplated inwhich the bandwidth manager dynamically allocates additional bandwidthdepending upon subscriber requests or needs. For example, the bandwidthmanager detects a request by a subscriber destination for a service thatrequires a greater amount of bandwidth than the subscriber destinationis currently allocated, and dynamically allocates additional unsharedbandwidth to the requesting subscriber destination in order to handlethe requested service.

[0017] The bandwidth manager is also useful for monitoring bandwidthusage of each of the subscriber destinations. This may be achieved bymonitoring data flow through the switch, such as tracking data flowthrough the first array of the switch matrix between the switch and thesubscriber destinations. The bandwidth manager may track overallbandwidth and may further track bandwidth usage based on service type.For example, the bandwidth manager tracks source information provided toeach subscriber to determine service type allocation and usage. Suchmonitoring and tracking capabilities are useful for various purposes,such as billing subscribers based on actual service usage.

[0018] An address resolution server may be provided to reduce oreliminate subscriber broadcast traffic in the network. It is desiredthat broadcast traffic be substantially reduced to maintain sufficientbandwidth in the network to meet subscriber needs. In one configuration,for example, the address resolution server stores an address databasethat cross-references logical and physical addresses. The addressresolution server is operative to respond to a physical address requestby retrieving and forwarding the physical address based on a logicaladdress. In one embodiment, for example, a gateway device is provided ateach subscriber destination. A broadcast address resolution protocol(ARP) request submitted by a local subscriber device is captured by thegateway device and converted to unicast format. The unicast request isforwarded to the address resolution server, which retrieves therequested physical address and responds to the request. The requestingdevice is then able to communicate with the located device in thenetwork on a direct and point to point basis. Thus, broadcast packetsfrom subscriber destinations are avoided and broadcast traffic issubstantially reduced. The address resolution server may be configuredto forward a broadcast address resolution request in the event thephysical address is not found in its local address database. In thislatter embodiment, however, the address resolution server is furtherconfigured to detect and halt abuse of such capability. For example, theaddress resolution server detects a particular subscriber destinationsubmitting more than a predetermined number of such requests with one ormore unknown addresses, or detects a predetermined number ofunsuccessful attempts by a subscriber destination in which the addressis never located in the network. In either case, the subscriberdestination's further requests are denied to prevent continued abuse.

[0019] In particular embodiments, each subscriber destination isprovided with a gateway device or the like. The gateway device includesa tuner that is tuned to one or more assigned channels to extractmodulated information, such as modulated information in an electricalsignal delivered via a coaxial cable in a hybrid fiber coax (HFC)network. The gateway device further includes a demodulator thatdemodulates the extracted modulated information into the sourceinformation. The extracted source information is in digital format andmany variations are contemplated depending upon the configuration atspecific subscriber destinations. In one embodiment, the gateway deviceincludes a gateway switch that that forwards source information to oneor more subscriber devices based on address information in the sourceinformation. The gateway device may further include one or moreconverters that convert source information to an appropriate format fora corresponding subscriber device. For example, the gateway device mayinclude a video converter that converts source video information intovideo data that is forwarded to a set top box. Digital video data may beconverted into analog format for delivery directly to a television. Thegateway device may include an audio converter that converts digitalaudio data into telephone analog signals that are provided to a localtelephone. Of course, many other types of converters are contemplated.

[0020] The gateway device may further include management and controllogic or the like that controls operations of the gateway devicedepending upon its configuration. In one embodiment, the managementlogic monitors bandwidth usage of the subscriber destination andforwards bandwidth usage information to the point of distribution. Thebandwidth usage information may be aggregate information only or mayfurther detail service type usage at the subscriber destination. Asdescribed previously, the point of distribution may include a bandwidthmanager that receives and stores the bandwidth usage information. Thedistributed gateway device embodiment provides a more convenientmechanism to track bandwidth and/or service type usage and simplifiesthe bandwidth manager server configuration. The management and controllogic may also be programmed or otherwise include logic to detect aphysical address request in broadcast format from a local subscriberdevice, to convert the request to unicast format, and to forward theunicast physical address request to the point of distribution to reducebroadcast traffic as previously described.

[0021] The gateway device may further be programmable to be dynamicallytuned to any assigned channel. A channel switch command or the likereceived from the point of distribution causes the tuner to switch fromone channel to another. The command may be received directly by thetuner, or may be received by the management and control logic whichcontrols or otherwise commands the tuner to perform dynamic channelswitching. The gateway device may further include an optional buffer orthe like that temporarily receives and stores data while the tuner ischanging channels to facilitate seamless switching.

[0022] The gateway device also facilitates upstream traffic. In oneembodiment, the gateway device includes a modulator that modulatessubscriber information from a subscriber device and an up converter thatconverts modulated subscriber information to an RF signal into anassigned subscriber upstream channel. The up converter transmits theupstream RF signal to the point of distribution via the network, such asvia coaxial cable to an optical transceiver node in an HFCconfiguration. The gateway device may further include one or moreconverters that convert the subscriber information into digital formatbefore being provided to the modulator. A computer or set top box or thelike may already include such conversion capability so that it would notbe necessary in the gateway device. Other devices, such as analogtelephones, televisions, security interfaces, utility interfaces, etc.may send data that requires conversion prior to modulation.

[0023] As described above, the combined signal delivered to subscriberdestinations may include broadcast television information. In suchembodiments, the gateway device may further include a splitter or thelike that splits broadcast content from the combined signal. Dependingupon its format, the broadcast content may be provided directly to asubscriber device, such as a set top box or television or the like, ormay be converted, such as by a video converter or the like within thegateway device, before being provided to the subscriber device. Manyother configurations and embodiments of the gateway devices arecontemplated. For example, the tuner may be statically or dynamicallyprogrammable to switch to any other subscriber channels. For dynamicbandwidth allocation, for example, the bandwidth manager may beconfigured to remotely and dynamically re-tune the gateway device to adifferent subscriber channel. This dynamic tuning capability enables thebandwidth manager to dynamically move subscriber destinations todifferent subscriber channels to more efficiently utilize bandwidthand/or to dynamically increase bandwidth allocation to one or moresubscriber destinations. A dynamically tunable gateway device mayfurther include a buffer or the like to facilitate seamless switching.In the alternative or in addition, each gateway device may be tuned tomultiple consecutive subscriber channels to maximize bandwidthallocation to any one or more subscriber destinations.

[0024] A communication system for enabling communication between a pointof distribution and a plurality of subscriber destinations via an HFCnetwork, according to embodiments of the present invention, includes anoptical plant, a point of distribution, a coaxial cable distributed toone or more subscriber destinations and an optical transceiver node thatinterfaces the optical plant and the coaxial cable. The point ofdistribution includes a multi-port switch, one or more RF modems, acombiner and a transmitter that converts a combined signal to an opticalsignal and that transmits the optical signal via the optical plant. Theoptical transceiver node converts the optical signal to an electricalsignal and transmits the electrical signal to the subscriberdestinations via the coaxial cable. The optical transceiver node furtherincludes an optical converter that converts a plurality of upstream RFsignals from the coaxial cable into an upstream optical signal and thattransmits the upstream optical signal to the point of distribution viathe optical plant.

[0025] A communication system for distributing information via anoptical network, according to the present invention, includes an opticalplant, a point of distribution, one or more fiber optic cables eachrouted to a describer destination and a wavelength division multiplex(WDM) selector. The point of distribution includes a switch and opticaltransceivers and a WDM combiner that combines an optical source signalfrom each transceiver into a combined optical signal and that transmitsthe combined optical signal onto the optical plant. The WDM selectorreceives and separates the combined signal from the WDM combiner intoits individual optical signal components and forwards each separateoptical signal over a corresponding one of the fiber optic cables to asubscriber destination.

[0026] A method of distributing information by a point of distributionto subscribers via a communication network, according to embodiments ofthe present invention, includes dividing a television broadcast spectruminto one or more subscriber channels, each subscriber channel having adeterministic bandwidth, allocating unshared bandwidth to eachsubscriber destination, assigning each subscriber destination to asubscriber channel, forwarding source information to each subscriberdestination based on assigned subscriber channels, modulating sourceinformation for each subscriber channel, up converting modulated sourceinformation into a corresponding subscriber channel, combining modulatedinformation from each subscriber channel into a combined signal, anddistributing the combined signal to the subscriber destinations via thecommunication network. The method contemplates many variations such assimilar to the apparatus variations described above.

[0027] A method of communicating information between a point ofdistribution and one or more subscriber destinations via a hybrid fibercoax (HFC) delivery plant according to embodiments of the presentinvention includes the point of distribution dividing a televisionbroadcast spectrum into one or more subscriber channels, each subscriberchannel having a deterministic bandwidth, allocating unshared bandwidthto each of one or more subscriber destinations, assigning eachsubscriber destination to a subscriber channel, forwarding sourceinformation to each subscriber destination based on assigned subscriberchannels, modulating source information for each subscriber channels, upconverting modulated source information into a corresponding subscriberchannel, combining modulated information from each subscriber channelinto a combined signal, converting the combined signal into an opticalsignal, and transmitting the optical signal to an optical transceivernode via an optical plant. The method further includes an opticaltransceiver node converting the optical signal into a combinedelectrical signal, and transmitting the combined electrical signal via acoaxial cable to each of the subscriber destinations. Again, the methodcontemplates many variations such as similar to the apparatus variationsdescribed above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] For a more complete understanding of the present invention,reference is now made to the following description taken in conjunctionwith the accompanying drawings in which like reference numerals indicatelike features and wherein:

[0029]FIG. 1 is a block diagram of a communication network according toan exemplary embodiment of the present invention including a switchedhierarchy and assigned subscriber channels;

[0030]FIG. 2 is a simplified block diagram of an exemplary embodiment ofa switch matrix that may be used in conjunction with the communicationnetwork embodiments described herein;

[0031]FIG. 3 is a block diagram of a communication network that issimilar to the communication network of FIG. 1 except employing adifferent allocation of the television broadcast spectrum and assignedchannels;

[0032]FIG. 4 is a block diagram of a communication network 400 that issimilar in function to either of the communication networks of FIGS. 1and 3 except employing an optical transmission pathway;

[0033]FIG. 5 is a block diagram of communication network of FIG. 4including an optical switch;

[0034]FIG. 6 is a block diagram of an alternative embodiment of aportion of the RF modems of FIG. 1 for reducing the number of upconverters at the point of distribution;

[0035]FIG. 7 is a block diagram of an exemplary embodiment of thegateways of FIG. 1; and

[0036]FIG. 8 is a block diagram of an exemplary embodiment of thegateways of FIG. 3 including a splitter for filtering televisionbroadcast information.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0037] The present invention provides a system and method for deliveringdigital or analog information to subscribers via allocated, unshared,bi-directional and deterministic bandwidth over a network. The presentinvention increases available bandwidth to subscribers or otherwiseimproves quality of service by providing unshared and dedicatedbandwidth rather than shared and non-deterministic bandwidth. Thenetwork may be implemented in any desired manner, such as a hybrid fibercoax (HFC) network, an all-optical fiber network, etc.

[0038] The HFC network is a wired, two-way communication network basedon radio frequency signals of the type received by television receivers.The HFC network uses linear fiber optics to transmit signals from acable headend or distribution hub to an optical transceiver node closeto subscriber destinations. A conventional coaxial transmission line busstructure may be used, usually with inexpensive radio frequency (RF)amplifiers as needed to cover the distance between the opticaltransceiver and subscriber's home. Individual subscribers are connectedto the coaxial bus using coaxial line drops tapped from the cable toprovide individual end-user network connections. Upstream and downstreamsignals reside on the same coaxial cable, separated in frequency. Theoptical transceiver node includes an optical converter that asserts thecomposite upstream signals from subscribers to the cable headend ordistribution hub via the optical plant. The optical plant may be asingle cable or separate upstream and downstream cables depending uponthe optical mode of transmission.

[0039]FIG. 1 is a block diagram of a communication system 100implemented according to an exemplary embodiment of the presentinvention. The communication system 100 receives information from asource 101 and delivers the source information to one or more subscriberdestinations 109 via a point of distribution 103 and a hybrid fiber coax(HFC) distribution network. The source information includes video,audio, data signals and the like, which may be in any of many differentformats. In exemplary embodiments, the source information is convertedto and/or delivered in frames or packets, such as internet protocol (IP)packets or Ethernet packets or the like, although other digital formatsare contemplated including fixed size frames or cells, such as used bythe Asynchronous Transfer Mode (ATM) network technology. Any type ofdigital information in fixed- or variable-sized frames, packets or cellsis referred to herein as “packetized” data. The packetized data includesone or more destination addresses or the like indicating any one or moreof the subscriber destinations 109 or indicating specific subscriberdevices at the subscriber destinations 109. The point of distribution103 may be a headend or originator of content, such as includingsatellite receivers and associated equipment and the like, or maycomprise a downstream communication or distribution hub coupled to aheadend facility. Thus, there may be one or more points of distribution103 serving a relatively large geographic area.

[0040] The source 101 incorporates or otherwise represents any one ormore electronic communication networks or devices, such as the internet,the public switched telephone network (PSTN), satellite communications,etc., and may represent or otherwise include a headend facility. Thepoint of distribution 103 is coupled to the source 101 through one ormore content server computers that convert or otherwise deliver data andcontent between the point of distribution 103 and the source 101. Forexample, the point of distribution 103 may include one or more videoservers (VID) 111 that communicate video content, one or more computernetwork servers (COMP) 113 that enable communication with the internetor other computer networks, and one or more telephone network servers115 that enable communication with the PSTN or other telephonic network.The illustrated servers 111-115 are exemplary only and other types ofservers and content are contemplated. Each of the servers 111-115represents one or more server computers and includes any additionalfunctionality as necessary or desired. For example, the VID servers 111may incorporate one or more video functions including video-on-demand(VOD) and may further include an MPEG converter or the like thatconverts broadcast video content from analog to digital or otherwisetranscodes video content from one digital form to another. The telephonenetwork servers 115 may include or otherwise incorporate one or moretelephone switches or the like.

[0041] The point of distribution 103 farther includes a switch 119coupled to the servers 111 115 and further coupled to a number (N) ofradio frequency (RF) modems 121 via corresponding ports of the switch119. The RF modems 121 are individually referenced as 121-X, where “X”is a positive integer from 1 to N and where “N” is a positive integergreater than one. Each server 111-115 converts or translates informationinto packetized format for

[0042] communication with the switch 119. In one embodiment, the switch119 is an Ethernet-type switch that forwards Ethernet packets betweenthe servers 111-115 and the RF modems 121. Each data packet includessource and destination addresses enabling the switch 119 to forward thepackets from a source to the appropriate destination. For example, theswitch 119 retrieves addresses from data packets from each server andforwards the packets to one of the RF modems 121 based on the addresses.Likewise, the switch 119 forwards subscriber and other packetizedinformation from the RF modems 121 to the servers 111-115 for deliveryto the source 101. In more particular embodiments, the switch 119includes one or more 100 BaseT Fast Ethernet switches that operate at adata rate of 100 Mbps, or one or more 1000 BaseT Gigabit Ethernetswitches that operate at 1 gigabit per second (Gbps). It is understoodthat the present invention is not limited to any particular switchtechnology and that other network architectures and technologies may beused, such as Asynchronous Transfer Mode (ATM) switches and the like.

[0043] Each RF modem 121 includes a modulator (MOD) 122 coupled to an upconverter (U/C) 123 and a tuner 124 coupled to a demodulator (DEMOD)126, which are devices known to those having skill in the art. Themodulator 122, the up converter 123, the demodulator and the tuner 124of each RF modem 121 may be incorporated into a single component or maybe implemented into any number of separate components. Although onlythree RF modems 121-X are shown, it is understood that the communicationsystem 100 is scalable so that any number of RF modems 121 may beemployed as indicated by the designation N.

[0044] The source information from the switch 119 is modulated by eachmodulator 122 of each RF modem 121 into an intermediate frequency (IF).The corresponding up converter 123 then up converts a corresponding IFsignal into one of multiple RF channels of the television broadcastspectrum, where each channel has a predetermined bandwidth. Theparticular frequencies employed by each modulator 122 and up converter123 depends on the particular configuration. In one embodiment, forexample, each modulator 122 is configured to separately modulate towithin approximately the same intermediate frequency range, such as aselected frequency between 1-60 MHz. Each corresponding up converter 123then converts by a different frequency level to change the IF signalinto a desired RF frequency channel assigned to that RF modem 121. Inthis first case, each up converter 123 employs a different carrierfrequency, separated by a predetermined frequency channel width, toenable separation of the assigned channels in the RF spectrum. In analternative embodiment, each modulator 122 modulates the sourceinformation into a respective one of a plurality of different IFsignals, each separated by a predetermined frequency channel width. Eachup converter 123 then up converts by approximately the same frequencylevel, so that the IF signals are up converted into an assigned RFchannel of a corresponding RF modem 121.

[0045] The RF signals from each of the RF modems 121 are then providedto respective inputs of a combiner 125, which combines the RF signalsfrom the RF modems 121 into a single combined electrical signal that isprovided to an optical transmitter 127. The combiner 125 essentiallyaggregates the RF signals from each of the assigned channels into anaggregate electrical signal for bulk transmission. The opticaltransmitter 127 converts the combined electrical signal to opticalsignals by a laser and transmits the optical signals via a fiber opticcable 133 to an optical transceiver node 105. It is noted that the pointof distribution 103 may transmit to more than one optical transceivernode, each similar to the node 105 and that serves a differentgeographic serving area. The node 105 receives the optical signal andconverts it back to a replica of the combined electrical signal anddistributes the combined electrical signal over a coaxial cable 137 toeach of several subscriber destinations 109 of a geographic serving area107.

[0046]FIG. 6 is a block diagram of an alternative embodiment of aportion of the RF modems 121 for reducing the number of up converters atthe point of distribution 103. An array of RF modems (MOD) 601 is shownin groups (a first group including MOD 1 to x, a second group includingMOD x+1 to y, etc.), where each RF modem 601 is similar to the RF modems121 except excluding the up converter 123. The modulated IF signal fromeach of the RF modems 601 are provided to respective inputs of one ormore combiners 603, individually shown as C1, C2, etc., where the outputof each combiner 603 provides a combined intermediate signal. Theoutputs of each of the combiners 603 are provided to a corresponding upconverter 605, individually shown as U/C 1, U/C 2, etc., where each upconverter 605 converts a corresponding IF signal by appropriate one ormore frequencies to provide a combined RF signals into the desiredchannels. The output of each up converter 605 is then provided to arespective input of the combiner 125 to provide a combined electricalsignal in a similar manner as previously described. The configurationshown in FIG. 6 illustrates an alternative embodiment in which one ormore of the up converters 123, which are often the more expensivecomponent, are combined into a single up converter 603 for improvedefficiency and reduced cost.

[0047] Referring back to FIG. 1, the geographic serving area 107includes M subscriber destinations 109 (individually referenced as109-X, where “X” is a positive integer from 1 to M and where “M” is apositive integer greater than one). In one embodiment, the number M ofsubscriber destinations 109 may be maintained at a predetermined maximumand/or the distance traversed by the coaxial cable 137 is limited to apredetermined maximum distance, such as a substantially reduced distanceas compared to conventional cable configurations. Such maximum valuesare chosen to reduce line losses across the coaxial cable 137 to a levelthat is not significant enough to effect network performance. In oneembodiment, for example, a maximum distance of one thousand feet and amaximum number of 150 subscriber destinations 109 is maintained for eachgeographic serving area. This architecture eliminates the need foramplifiers as required by legacy cable systems. Further, the noise levelon the network including the coaxial cable 137 is substantially reduced,thereby improving communications, particularly upstream communications.A reduced number of subscriber destinations 109 provide greaterbandwidth per subscriber, which is particularly advantageous to increasethe bandwidth for upstream communications. Also, the complexity orsophistication of the communication equipment, such as at each node 105,is reduced, thereby reducing cost of the equipment and cost ofmaintenance of the equipment over time. It is understood, however, thatthe communication system 100 provides many advantages regardless ofspecified distances, the number of subscribers or the use of amplifiers.The present invention contemplates technologies that enable increaseddistance and/or number of houses that can be serviced without usingamplifiers. Also, although only one geographic serving area 107 isshown, the point of distribution 103 may interface multiple opticaltransceiver nodes, each node serving a different geographic servingarea.

[0048] The N RF modems 121 collectively service the M subscriberdestinations 109 of the geographic serving area 107 via the opticaltransceiver node 105. Of course, the point of distribution 103 mayinclude additional RF modems 121, combiners 125 and optical transmitters127 to service additional geographic service areas via correspondingoptical nodes 105 depending upon particular cable configurations. In oneembodiment, N and M are chosen to be equal to provide a one to onecorrespondence between the RF modems 121 and the subscriber destinations109. In this embodiment, each subscriber destination 109 is allocatedthe entire bandwidth provided by a corresponding one of the RF modems121.

[0049] It is noted that it is not necessary or even desirable that thenumber of RF modems 121 be equal to the number of subscriberdestinations 109. The amount of bandwidth provided by each RF modem 121may exceed the bandwidth requirements of any two or more subscriberdestinations 109. Also, the bandwidth provided by each of the RF modems121 is divisible to serve two or more subscriber destinations 109. In aparticular embodiment, for example, each RF modem 121 is configured toprovide a downstream bandwidth of approximately 40 Mbps, which mayfurther be allocated into 5 Mbps bandwidth increments at any given time.Thus, each RF modem 121 may serve up to 8 different subscriberdestinations 109, each with 5 Mbps of downstream bandwidth. In morepractical configurations, therefore, M is significantly greater than Nto maximize usage of the RF modems 121. It is further noted thatadditional or “reserve” RF modems may be provided to provide a morerobust system. In the event of failure of an operational RF modem, areserve RF modem is activated to replace the failed RF modem 121. In oneembodiment, each of the RF modems 121 may be fixed to a particularchannel of operation. In a more practical embodiment, each RF modem 121is programmable to operate in any of the channels for greaterflexibility.

[0050] In any of these embodiments and as described more fully below, adedicated and unshared data pathway is established between the point ofdistribution 103 and each subscriber destination 109 so that eachsubscriber has allocated, unshared, bidirectional and deterministicbandwidth. In one embodiment, the amount of bandwidth available to anygiven subscriber 109 is programmable to meet that particularsubscriber's bandwidth needs. For example, a subscriber signs up for andis granted a selected one of multiple bandwidth allocations, where theselected bandwidth allocation is always available to the subscriberdestination regardless of actual usage by that subscriber or any othersubscriber. In more flexible configurations, the bandwidth allocation isdynamically configurable and may be modified based on the subscriber'sneeds or requests on the fly or when requested. For example, regardlessof an initial bandwidth allocation granted to a subscriber (e.g. 10Mbps), that subscriber may temporarily request a greater amount ofbandwidth (e.g. 20 Mbps) for a particular application, such as a videoconference or the like.

[0051] Each of the subscriber destinations 109 includes a correspondinggateway 139, where each gateway 139 is coupled to the coaxial cable 137and tuned to one or more channels established by the RF modems 121. Thegateways 139 are individually referenced as 139-X, again where “X” is apositive integer from 1 to M. In this manner, the combined electricalsignal from the node 105 is received via the coaxial cable 137 by eachgateway 139 of the geographic serving area 107. Each gateway 139 isfurther coupled to one or more additional subscriber devices, such as aset top box 141, a telephone 145, a computer 147, a security interface149 and a remote utility interface 151. The television 143 is coupled tothe set top box 141. It is understood that the listed and shownsubscriber devices are exemplary only, where each subscriber destination109 may include any number, more or less, of subscriber devices otherthan that illustrated. Also, each gateway 139 may be configured toforward data to any other type of subscriber device (not shown) that isconfigured to process the received data.

[0052]FIG. 7 is a block diagram of an exemplary embodiment of thegateways 139. Each gateway 139 includes a tuner 701 that is tuned to atleast one channel of the combined electrical signal on the coaxial cable137. In one embodiment, for example, each gateway 139 is tuned to acorresponding downstream channel of the television broadcast spectrum,such as a corresponding 6 MHz channel modulated by a corresponding RFmodem 121. Each gateway 139 also includes a demodulator 703 thatextracts the source information in the form of packetized data from theassigned channel. Each gateway 139 further includes a multi-port switch705 or the like that forwards extracted source information to one of thesubscriber devices, including the set top box 141, the telephone 145,the computer 147, the security interface 149 or the utility interface151, through corresponding (and optional) interface (I/F) modules 707coupled between ports of the switch 705 and the input/output (I/O)connectors of the gateway 139. The switch 705 selectively forwards thepacketized source information based on addressing information within thepackets, such as a MAC physical address or an IP address or the like.Since a given channel may include source information intended formultiple subscriber destinations 109, the switch 705 drops or discardspackets with an address that is not recognized or otherwise intended fora different subscriber destination 109. Each interface module 707includes any necessary converters or the like to enable communicationbetween the switch 705 and the particular subscriber device connectedthereto.

[0053] The tuner 701 of each gateway 139 may be implemented in any oneof several different manners depending upon the particular operation andnetwork configuration desired. In one embodiment, the tuner 701 iseffectively assigned and tuned to a corresponding downstream channel,which is enabled by one of the RF modems 121. The tuner 701 effectivelyextracts all of the source information from an associated RF modem 121,regardless of whether the information is intended for the correspondingsubscriber destination 109. The switch 705 filters and drops sourceinformation not intended for that subscriber destination 109. Of course,the subscriber destination 109 may be allocated the entire bandwidth ofa channel provided by a corresponding RF modem 121.

[0054] In another embodiment, each tuner 701 is programmable and may bedynamically tuned to any other channel. Such dynamic tuning isadvantageous for various reasons, including the ability to switch to asecond RF modem 121 in the event of failure of a first. Another benefitof dynamic tuning is the ability to switch to a different channel and RFmodem 121 in the event of a change in bandwidth allocation and/or toincrease available bandwidth utilization. For example, a subscriberdestination 109 may request increased bandwidth that is not availablefrom its current RF modem 121 that is also serving one or moreadditional subscriber destinations 109. Dynamic tuning enables the tuner701 to be switched to a different RF modem 121 that has sufficientbandwidth to handle the requested bandwidth. Also, one or moresubscriber destinations 109 utilizing lower bandwidth may be moved orrepositioned to free up one or more RF modems 121 to provide greaterbandwidth to one or more other subscriber destinations 109. Additionalbuffering may be provided within each gateway 139 to facilitate seamlessswitching from one RF modem to another. In yet another embodiment, eachtuner 701 may further be capable of tuning to multiple consecutivechannels, which effectively multiplies the available bandwidth to thecorresponding subscriber destination 109. For example, in aconfiguration with 6 MHz channels, a tuner 701 may be configured to tuneto incorporate up to five or more channels to retrieve up to 30 MHz ormore, which corresponds to up to 200 Mbps or more potential bandwidth ata single location.

[0055] Each gateway 139 also contains a processor, additional software,firmware or the like, collectively shown as manager/control block 709coupled to another port of the switch 705, to control its operation andeach of the interface modules 707 associated with each of the othersubscriber devices. The manager/control block 709 may also be coupleddirectly to one or more of the interface modules 707. The software maybe programmed to control one subscriber device when a differentsubscriber device receives a signal (e.g., turning down the volume ofthe subscriber's television set when a telephone call is received). Inone embodiment, each gateway 139 forwards digital data directly to thecorresponding telephone 145, which includes conversion circuitry toconvert the digital signals to the necessary format for enablingtelephonic communications. In another embodiment, one of the interfacemodules 707 includes a converter that converts telephonic digitalinformation to plain old telephone service (POTS) analog signals forconsumption by the telephone 145 coupled to that interface module 707,and for converting POTS signals from the telephone 145 to digitalsignals for transmission back to the point of distribution 103.

[0056] Each gateway 139 provides the benefit of allowing theprovisioning of the additional services, such as the telephone,security, utility and computer services, which are likely to be locatedat different physical locations in the subscriber's home. Thus, eachgateway 139 forwards source information to the appropriate or addressedsubscriber device in the subscriber's home. Additionally, each gateway139 allows the subscriber destination 109 to send subscriber informationupstream to the point of distribution 103 (e.g., utility meter data).Each gateway 139 provides another advantage in that it may be installedoutside of the subscriber's house. This allows each gateway 139 and itsdata signals to be insulated from the RF noise and interferenceoccurring in the subscriber's home and further facilitates tapping intothe various other receiving devices in the subscriber's home.

[0057] The electrical RF signal on the coaxial cable 137 includes apoint-to-point RF data signal within the assigned channel for eachgateway 139. The RF data signal may be transmitted either based on aspecific subscriber request (e.g., a request for television content orInternet content) or based on a standing subscriber request (e.g., alltelephone data addressed to a subscriber's telephone number). Forexample, the set top box 141-1 converts television broadcast digitalinformation into analog signals for consumption by a correspondingtelevision 143-1. Movie-type data packets are sent to an MPEG decoder inthe set top box 141-1 for decoding from data to video for display ontelevision 143-1. Internet or Ethernet type data packets are sent to thecomputer 147-1. In a similar manner, telephonic information is forwardedto the telephone 145-1, security information is forwarded to thesecurity interface 149-1, and utility information is forwarded to theutility interface 151-1. It is noted that many variations of theparticular embodiment shown are contemplated. For example, the gateway139 and its corresponding functions provided at any one or more of thesubscriber destinations 109 may be incorporated into one of thesubscriber devices, such as the set top box 141, or may be incorporatedinto a different subscriber device, such as a cable modem or the like.

[0058] The communication system 100 also includes a return or “upstream”data path from the subscriber destinations 109 to the point ofdistribution 103. As shown in FIG. 7, each gateway 139 also includes amodulator 711, coupled to a port of the switch 705, that modulatessubscriber information received from any of the subscriber devices 141,143, 145, 147, 147 or 151 (141-151) into an IF signal. An up converter713 is coupled to the modulator 711, where the up converter 713 upconverts the modulated IF signal from the modulator 711 into an RFsignal in an upstream channel. The up converter 713 asserts a return orsubscriber or “upstream” RF signal onto the coaxial cable 137. The datasignal is thus converted by the gateway 139 to an RF signal and placedwithin an upstream channel by the gateway modem and up converter.

[0059] As described previously, the tuner 701 may be programmable sothat it be dynamically tuned to any other channel handled by a differentRF modem 121. As described more fully below, a channel switch command issent by the point of distribution 103 to the gateway 139 indicating anew channel. The channel switch command is received directly by thetuner 701, which then performs the channel switch in response.Alternatively, the command is forwarded to the manager/control block709, which then commands or otherwise controls the tuner 701 to performthe channel switch via a control link 717 or the like. An optionalbuffer 715 is provided and coupled to the tuner 701, to the up converter713 and to the coaxial cable 137 to temporarily receive and store datawhile the tuner 701 switched to facilitate seamless switching.

[0060] Referring back to FIG. 1, the upstream RF signals from each ofthe subscriber destinations 109 are transmitted on the coaxial cable 137back to the node 105. A separate upstream channel of the upstreamportion of the television broadcast spectrum may be assigned to each ofthe subscriber destinations 109 to prevent interference with downstreamcommunications. The upstream RF signals are provided to the node 105,which includes an upstream optical transceiver that converts thesubscriber RF signals to an optical signal. A laser in the node 105 isused to convert the return signal to an optical signal and send theoptical return signal to an optical receiver 129 at the point ofdistribution 103 over another fiber optic cable 135. It is noted thatthe optic cables 133, 135 may comprise a single cable or optic plantdepending upon the particular configuration. The optical receiver 129converts the combined optical signal to a combined subscriber electricalsignal, which is provided to a splitter 131. The splitter 131 duplicatesand forwards the combined subscriber electrical signal to a respectivetuner 124 of each of the RF modems 121. Each tuner 124-X is tuned to oneor more upstream channels assigned to that particular RF modem 121, andextracts a corresponding return RF signal. Each tuner 124 provides theextracted return RF signal to a corresponding demodulator 126-X, whichdemodulates the return RF signal into the corresponding subscriber datapackets sent from one or more of the subscriber destinations 109associated with that RF modem 121. The subscriber information datapackets are then forwarded to the switch 119 for processing andforwarding.

[0061] It is noted that many different modulating frequencies andtechniques are contemplated for both downstream and upstreamcommunications. Modulation techniques may include, for example,Frequency Shift Keying (FSK), Quadrature Phase-Shift Keying (QPSK), aswell various types of Quadrature Amplitude Modulation (QAM), such as QAM16, QAM 64, QAM 256, etc., among other modulation techniques. Also, eachchannel may have any predetermined bandwidth, such as 3 MHz, 6 MHz, 12MHz, etc. Each channel typically includes a separate downstream andupstream channel separated in frequency, where the corresponding downand up stream channels may have the same or different channel width.Further, the modulation technique employed for each downstream channelmay be the same or different than the modulation technique employed foreach upstream channel. A simpler modulation technique employed forupstream communications enables a simpler and less expensive gateway orcable modem design at each subscriber destination 109. In an exemplaryembodiment, for example, each channel includes a 6 MHz downstreamchannel and a 2 MHz upstream channel. Using QAM 256 modulation for thedownstream 6 MHz channel (at approximately 5.36 usable MHz) enables araw data rate of approximately 42 Mbps. Using QAM 64 modulation for theupstream 2 MHz channel (at approximately 1.8 usable MHz) enables a rawdata rate of approximately 11 Mbps per subscriber destination 109.

[0062] Of course, many different variations and alternatives arepossible and contemplated without departing from the scope of thepresent invention. In one embodiment, the downstream bandwidthallocations are greater than the upstream bandwidth allocations.Alternatively, the down and up stream allocations are equal orsubstantially equivalent to achieve a symmetrical configuration. Ofcourse, if the communication system 100 is configured with dynamicbandwidth allocation, bandwidth allocations may be modified based onsubscriber needs.

[0063] In an exemplary high split system configuration, the available RFspectrum of 5-860 MHz is divided into an upstream range of 5-188 MHz anda downstream range of 238-860 MHz, where the diplex filter is locatedapproximately within the frequency range 188-238 MHz. This configurationis exemplary only and illustrates a more balanced frequency spectrum fordown and up streams. Also, assume each down and up stream channel has achannel width of 6 MHz based on the existing cable plant in the UnitedStates. In the first embodiment described above where each modulator 122modulates to approximately the same intermediate frequency, the first upconverter 123-1 up converts by a carrier frequency of f₀ MHz, the nextup converter 123-2 up converts by a carrier frequency of f₁=f₀+6 MHz,the next up converter 123-3 up converts by a carrier frequency off₂=f₁+6 MHz and so on, resulting in separate RF signals at channels ofapproximately 238-244 MHz, 244-250 MHz, 250-256 MHz, etc. In the secondembodiment where each modulator 122-1, 122-2, 122-3, etc. modulates todifferent intermediate frequencies separated by a predetermined channelwidth, such as 6 MHz, then each of the up converters 123 up converts byapproximately the same carrier frequency f_(C) resulting in the separateRF signals at the assigned downstream channels of approximately 238-244MHz, 244-250 MHz, 250-256 MHz, etc. Other systems are contemplated, suchas a mid-split system in which the diplex filter is locatedapproximately within the frequency range of 80-118 MHz, where each downand up stream channel has any convenient channel width.

[0064] In the communication system 100, a substantial portion or all ofthe available television broadcast spectrum is utilized to assignchannels to each of the subscribers. In this embodiment, the relativelylarge bandwidth currently unavailable using conventional televisionbroadcast networks (e.g., in the approximately 54-550 MHz range) isavailable for channel assignments rather than being allocated tobroadcast content. This provides an advantage over prior art networks byallowing the use of a very clean portion of the RF spectrum (e.g.,50-300 MHz). Each user may be allocated a greater amount of bandwidth ora greater number of subscribers may be served for each coaxial cable. Adifferent frequency spectrum split may be utilized to increase upstreambandwidth availability. Embodiments with a smaller geographic servingarea 107 provide a reduced noise node so that each subscriberdestination 109 receives a cleaner signal, typically without the needfor amplification. As described further below, bandwidth allocation iscontrolled by a bandwidth manager 161 coupled to a port of the switch119. The bandwidth manager 161 allocates each subscriber destination 109unshared, bidirectional and deterministic bandwidth. In other words, asa subscriber selects to receive different data (e.g., a differenttelevision “channel”), the set top box 141 (or 153) sends a message tothe bandwidth manager 161 via the switch 119, where the bandwidthmanager 161 responds by directing a corresponding one of the RF modems121 associated with the particular subscriber destination 109 to send adata signal with the requested data via the appropriate channel. Thebandwidth manager 161 may be configured to control the RF modems 121in-stream via the switch 119, or may be coupled directly to the RFmodems 121 to facilitate dynamic bandwidth allocation, tuning, failurerecovery, etc.

[0065] The communication system 100 is a fully switched hierarchy thatprovides composite bandwidth to make every requested data signal(requested from an subscriber destination 109) point-to-point (i.e.,sent from the point of distribution 103 to a particular subscriberdestination 109 rather than sending data signals in a broadcast ormulticast fashion), regardless of how many requests for the same datasignal exist on the communication system 100 at any one time. Thus, thedata signals are targeted and intended for each of the subscriber settop boxes 141 are output from the point of distribution 103 of thenetwork 100. A warp server 163, coupled to another port of the switch119, is provided to cooperate with each of the gateways 139 to enforceand maintain point-to-point communications and to keep broadcast and/ormulticast communications to a minimum.

[0066] In operation, there is available data in source 101 that asubscriber may want to receive. Specific requests for data are sent by asubscriber destination 109 (e.g., through the subscriber's gateway 139)and received by the switch 119 at the point of distribution 103 (i.e.,at a corresponding RF modem 121), which forwards the request for thespecified data to the bandwidth manager 161. Based on thissubscriber-initiated request, the bandwidth manager 161 forwards therequests to the appropriate one of the servers 111-115. It is noted thatthe embodiment shown is exemplary only and that any other informationmay be supported with the appropriate communication equipment. Therequest typically includes an address or the like identifying aparticular subscriber destination 109. The source 101 provides thesubscriber-requested data to the requesting server 111-115, whichforwards the information to the switch 119. The switch 119, in turn,forwards the data to the appropriate RF modem 121 for delivery to therequesting subscriber destination 109. The signal with thesubscriber-requested data flows to the subscriber destination 109 in themanner previously described.

[0067] The bandwidth manager 161 receives subscriber requests forparticular data from the node 105, initiates a request to have thesubscriber-requested data sent to the requesting subscriber destination109 and determines the subscriber request's effect on overall bandwidthavailability at the subscriber's gateway 139. For example, if asubscriber requests a different regular analog television data signal(i.e., a subscriber request to receive channel 42 rather than channel 36programming at a television set), the bandwidth manager 161 determinesthat the request has little or no effect on overall requested bandwidthand thus allows the requested data to be sent to the subscriberdestination 109. If, however, the request is a change from a regularanalog television data signal to a high definition television datasignal, the bandwidth manager 161 determines whether sufficientbandwidth is available to respond to the request to that subscriberdestination 109. If so, the bandwidth manager 161 approves the requestand allows the requested data to be sent to the requesting subscriberdestination 109. In a dynamic configuration, the bandwidth manager 161allocates a greater amount of bandwidth to the subscriber destination109 on a given RF modem 121, or switches to another RF modem 121 that isable to deliver the requested bandwidth. If the request cannot begranted or if sufficient bandwidth is not available, then the bandwidthmanager 161 blocks the request from the subscriber or, alternatively,delivers the data with quality limitations. In either case, thebandwidth manager 161 sends a message to the subscriber destination 109indicating insufficient bandwidth to accommodate the requested data.

[0068] In one embodiment, the bandwidth manager 161 monitors and storesallocated bandwidth usage by each of the subscriber devices 109 in thecommunication system 100. The bandwidth usage by each of the subscriberdevices 109 is tracked and stored in the aggregate and further byspecific service type. The bandwidth manager 161 may perform thesemonitoring functions by tracking packet transfers in the switch 119. Ina more practical embodiment, the manager/control block 709 of eachgateway 139 tracks bandwidth usage by the corresponding subscriberdestination by service type (e.g., phone, video-on-demand, internetusage, etc.) and in the aggregate. Each gateway 139 reports bandwidthusage to the bandwidth manager for tracking purposes. In this manner,the bandwidth manager 161 tracks total bandwidth of the communicationsystem 100, of each subscriber destination 109, and of each serviceconsumed at each subscriber destination 109. Such bandwidth usageinformation is useful for many purposes, including billing services,network management and control, and further control of particularservices provided to each subscriber destination 109 as desired. Forexample, the bandwidth manager 161 may be configured to receive arequest from a particular subscriber destination 109 for a particularservice, such as a video conference, a teleconference, avideo-on-demand, etc., allocate bandwidth for the service, and trackusage of the service for proper billing of the subscriber.

[0069] In any of the embodiments, the bandwidth manager 161 isconfigured to conduct and control dynamic tuning and bandwidthallocation capabilities. In this embodiment, the gateways 139 areconfigured to be dynamically tunable so that the bandwidth manager 161distributes the assignment of the gateways 139 to the RF modems 121 inany desired manner. The bandwidth manager 161 dynamic tuning andre-allocation as desired or necessary by sending one or more channelswitch commands to a corresponding one or more of the gateways 139 tore-assign the gateway(s) to another channel. As described previously,such dynamic tuning is advantageous for various reasons, including theability to switch a gateway 139 to another RF modem 121 in the event offailure of an RF modem 121 or in the event of a change in bandwidthallocation and/or to increase available bandwidth utilization. Forexample, a subscriber destination 109 may request increased bandwidththat is not available from its current RF modem 121 that is also servingone or more additional subscriber destinations 109. The bandwidthmanager 161 switches the corresponding gateway 139 to a different RFmodem 121 that has sufficient bandwidth to handle the requestedbandwidth. Also, one or more subscriber destinations 109 utilizing lowerbandwidth may be moved or repositioned to free up one or more RF modems121 to provide greater bandwidth to one or more other subscriberdestinations 109. The channel switch command may further be employed toprogram a gateway 139 to tune to multiple consecutive channels if thecorresponding subscriber destination 109 requests or otherwise needs asubstantial bandwidth allocation.

[0070] The warp server 163 and the gateways 139 are configured toreplace broadcast or multicast traffic in the communication system 100with point-to-point traffic. An example of such a broadcast packet is anAddress Resolution Protocol (ARP) request requesting the physicaladdress of a computer, where the ARP request includes a logical addressof the target computer. In a typical network configuration, ARP requestsare broadcast to every other computer in the network. Upon receipt, alldevices that do not have that logical/physical address ignore therequest, while the computer with the specified logical/physical addressresponds with a directed packet so that the requesting computer cansubsequently send directed data to that computer using the returnedphysical address. Broadcast and/or multicast traffic in thecommunication system 100 is not desired because it substantiallyincreases overhead and threatens to consume valuable bandwidth that ispreferably utilized to deliver content. Broadcast and multicast trafficis allowed from the point of distribution 103, but is either not allowedor otherwise substantially limited from the subscriber destinations 109.In the communication system 100, the warp server 163 maintains adatabase of addresses for each gateway 139 and other devices on thecommunication system 100. Each gateway 139 also includes additionalfunctionality, such as programmed within manager/control block 709, thatallows it to block broadcast packets from subscriber devices (143-151)or to convert broadcast packets to point-to-point ARP (addressresolution protocol) requests so that point-to-point communication isenforced throughout the communication system 100.

[0071] For example, a computer 147-x sends out an ARP request todetermine an address for another computer 147-y in the communicationsystem 100, where “x” and “y” are used to distinguish between differentcomputers within the geographic serving area 107. The gateway 139-xintercepts the broadcast ARP request from the computer 147-x, convertsthe ARP request to a warp request and sends the warp request in apoint-to-point manner to the warp server 163. The manager/control block709, for example, is programmed with this interception, conversion andforwarding capability. The warp request includes the information in theARP request, including, for example, the request for the physicaladdress of the computer 147-y to which the computer 147-x needs to senddata. The warp server 163 contains a database linking physical andlogical addresses of all devices in the communication system 100 and,upon receipt of the warp request, determines the physical address of thecomputer 147-y. The warp server 163 optionally sends a message to thecomputer 147-y identifying that data is coming from the computer 147-xand sends a message to the computer 147-x with the physical address ofthe computer 147-y so that the computer 147-x can send the datapoint-to-point. The computer 147-x sends a message to computer 147-y,where the message includes a source address identifying the computer147-x. In this manner, communication between the computer 147-x and thecomputer 147-y becomes point-to-point. The warp server 163 serves thisfunction to allow point-to-point communication between all devices inthe communication system 100.

[0072] The warp server 163 may allow a limited amount of broadcasttraffic initiated by the subscriber devices 109. For example, if an ARPrequest is received and the requested logical address is not found, thenthe warp server 163 may forward the request in broadcast format to eachdevice in the communication system 100 in a similar manner as a normalARP request. Such an unknown address request may occur, for example, ifnew and previously unknown devices are added to the network, such as anew subscriber destination 109 otherwise not known to the warp server163. Alternatively, unknown ARP requests are systematically denied,where new devices are programmed to reduce or eliminate the possibilityof unknown devices in the system. The warp server 163 tracks andterminates potential abuse of such broadcast traffic. For example,repeated ARP requests by a particular subscriber destination 109 aremonitored and terminated to prevent abuse or attack that could otherwiseconsume valuable bandwidth or interrupt service to any other subscriberdestination 109. Each gateway 139 serves to protect the communicationsystem 100 and the network from abuses by any particular subscriberdestination 109 or home networks.

[0073] One significant benefit of the communication system 100 shown isthe ability to deliver allocated, unshared, bidirectional anddeterministic bandwidth to individual subscribers. Thus, data destinedfor a particular subscriber destination 109 is assigned a specific andunshared bandwidth that is available only to that subscriber. Thisprovides the ability to deliver time-dependent or isochronous typeservices to each subscriber destination 109, such as video, voice overIP, bidirectional audio content (e.g., a telephone connection), etc.,that is not otherwise possible in a shared network. Downstream dataentering the network passes though a switch, which forwards the data toa port of the switch based on the subscriber for which it is destined.Upstream or subscriber data is forwarded to a respective RF modem, whichforwards packetized information to the switch. The switching equipmentis much less expensive than the costly instruction-based equipment usedin existing HFC networks.

[0074] The communication system 100 employs the entire televisionbroadcast spectrum for point to point communications and generally doesnot forward broadcast communications to all of the subscriberdestinations 109, as is typical for legacy cable television networks.Such configuration may not be suitable for consumer networks, for whichthe Federal Communications Commission (FCC) regulations may require plugand play broadcast television content. Thus, the communication system100 is particularly advantageous for business use in which broadcastcontent is generally limited or not provided. In a limited businessconfiguration, for example, one or more broadcast television stationsmay be available, such as a limited number of television channelsdirected towards education, local programming, weather, news, etc.

[0075]FIG. 2 is a simplified block diagram of an exemplary embodiment ofthe switch 119 a including a switch matrix 200 configured as a hierarchyof switches. The exemplary switch matrix 200 configuration includesmultiple levels of switches, each level configured as an array ofswitches for forwarding data between the servers 111-115 and the RFmodems 121. In particular, the matrix configuration includes a firstarray of switches 201-X coupled to the video servers 111, where “X” is apositive integer from 1 to “i” and where “i” is a positive integer. Eachswitch 201 is coupled to one or more of the RF modems 121 for forwardingvideo data between the video servers 111 and the subscriber destinations109 associated with that particular RF modem 121. In the exemplaryembodiment shown, for example, each switch 201 is coupled to a group ofthe RF modems 121, where each group includes “l” RF modems 121. Inparticular, the first RF modem 121-1 is coupled to a first group of RFmodems 121-1 to 121-l and so on up to a last switch 201-i coupled to afinal group of RF modems 121-N−l+1 to 121-N. It is noted that theembodiment shown is exemplary only, so that the number “l” of RF modems121 in each group and the number “i” of switches 201 are any appropriatenumbers depending upon the data capacity of each switch 201 andbandwidth requirements of the associated subscriber destinations 109.Also, the number of RF modems 121 in each group need not be equal andmay vary from group to group.

[0076] The matrix configuration further includes a second array ofswitches 203-X coupled to the computer network servers 113, where “X” isa positive integer from 1 to “j” and where “j” is a positive integer.Each switch 203 is coupled to one or more of the switches 201 forforwarding computer network data between the computer network servers113 and the subscriber destinations 109 associated with RF modems 121that are further coupled to that particular switch 203 via theintermediate switches 201. In the exemplary embodiment shown, forexample, each switch 203 is coupled to two of the switches 201. Inparticular, the first switch 203-1 is coupled to the first two switches201-1 and 201-2, the next switch 203-2 is coupled to the next twoswitches 201-3 and 201-4 and so on up to the last switch 203-j coupledto the last two switches 201-i−1 to 201-i. Again, the embodiment shownis exemplary only, so that the number of switches 201 coupled to eachswitch 203 and the number “j” of switches 203 are any appropriatenumbers depending upon the respective data capacities of the switches201, 203 and bandwidth requirements of the associated subscriberdestinations 109.

[0077] The matrix configuration further includes a third array ofswitches 205-X coupled to the telephone network servers 115, where “X”is a positive integer from 1 to “k” and where “k” is a positive integer.Each switch 205 is coupled to one or more of the switches 203 forforwarding computer network data between the telephone network servers115 and the subscriber destinations 109 associated with RF modems 121that are further coupled to that particular switch 205 via theintermediate switches 201, 203. In the exemplary embodiment shown, forexample, each switch 205 is coupled to two of the switches 203. Inparticular, the first switch 205-1 is coupled to the first two switches203-1 and 203-2 and so on up to the last switch 203-k coupled to thelast two switches 203-j−1 to 203-j. Again, the embodiment shown isexemplary only, so that the number of switches 203 coupled to eachswitch 205 and the number “k” of switches 205 are any appropriatenumbers depending upon the respective data capacities of the switches203, 205 and bandwidth requirements of the associated subscriberdestinations 109.

[0078] In one embodiment, the switch matrix 200 is configured into a“top-down” or pyramid configuration and organized to handle differentlevels of bandwidth at each level. For example, the number of switchesin each array may be such that i>j>k, so that the number of switches isincreased from the top to the bottom of the pyramid. A greater number ofthe switches 201 are provided at the base of the pyramid to effectivelyhandle a higher overall bandwidth. A medium number of the switches 203are provided in the middle of the pyramid to handle a medium amount ofbandwidth. A reduced number of the switches 205 are provided at the topof the pyramid to handle a lower amount of bandwidth. As shown, theswitches 201 coupled to the video servers 111 handle video data, whichtypically consumes a greater amount of bandwidth. Computer network data,which consumes a moderate amount of bandwidth and which may includesignificant upstream traffic, is processed via the switches 203 coupledto the computer network servers 113. Telephonic data is handled throughthe switches 205 coupled to the telephone servers 111.

[0079] Each switch 201 handles the data of each of the servers 111-115for the particular subscriber destinations 109 in the correspondinggroup of RF modems. In the particular embodiment shown, for example, theswitch 201-1 handles video, computer and telephonic data for thesubscriber destinations 109 associated with the first group of “l” RFmodems 121-1 to 121-l. The next switch 201-2 handles data for thesubscriber destinations 109 associated with the next group of “r” RFmodems 121, and so on. The switch 203-1 handles computer and telephonicdata for the subscriber destinations 109 associated with the RF modems121 coupled through the switches 201-1 and 201-2. The next switch 203-2handles computer and telephonic data for the subscriber destinations 109associated with the RF modems 121 coupled through the switches 201-3 and201-4, and so on. It is appreciated that each of the switches 201effectively isolates video data from being forwarded to the upper levelswitches 203, 205. In a similar manner, the switch 205-1 handlestelephonic data for the subscriber destinations 109 associated with theRF modems 121 coupled through the switches 203-1 and 203-2. The nextswitch 205-2 (not shown) handles computer and telephonic data for thesubscriber destinations 109 associated with the RF modems 121 coupledthrough the switches 203-3 and 203-4 (not shown), and so on. Again, eachof the switches 203 effectively isolates computer network data frombeing forwarded to the upper level switches 205. Although the servers111-115 may be coupled to the respective switch arrays 201, 203 and 205through single buses or connections, greater throughput is achieved withseparate connections to each switch, such as in a star configuration orthe like. Thus, video data from a video server 111 intended for asubscriber destination 109 coupled through the RF modem 121-1, forexample, is sent to switch 201-1 and not to any of the other switches201.

[0080] A manager switch 207 is provided in the switch matrix 200 andcoupled to each of the switches 205. The manager switch 207 includesadditional ports for further coupling the bandwidth manager 161 and thewarp server 163. Other than handling management information and trafficto and from the bandwidth manager 161 and the warp server 163, themanager switch 207 also handles subscriber to subscriber traffic. Forexample, the data for a cross POD video conference between two differentsubscriber destinations 109 or a phone call travels to and from themanager switch 207 in the switch matrix 200. It is appreciated thattwo-way communication is fully enabled in the switch matrix 200. In thismanner, the manager switch 207 is able to communicate with each of theswitches 201-205 in the switch matrix 200 via the switches 205, and viceversa. Further, the manager switch 207 communicates with each of thesubscriber destinations 109 via corresponding RF modems 121, and viceversa. Likewise, the bandwidth manager 161 and the warp server 163communicate with any device in the communication system 100 via themanager switch 207. Each of the switches 201-207 of the switch 119 maybe implemented using the same type of switch, or may be implemented asdifferent switch types that are tuned or selected based on the type ofdata or the bandwidth requirements associated with that switch or thatlevel. Also, although only three levels of switch arrays are shown, itis understood that any number of arrays may be implemented dependingupon the particular network configuration and operation.

[0081] The bandwidth manager 161, in combination with the switch matrix200, provides “statistically starved” capabilities. The statisticallystarved feature allows the switch matrix 200 to be built with less thanthe maximum bandwidth that would theoretically be needed if allsubscriber destinations 109 were using all services available over thecommunication system 100 simultaneously. In order to provide astatistically-starved switching capability, the switch matrix 200 isdesigned so that it is always operating significantly below its maximumbandwidth capacity. The bandwidth manager 161 monitors the operation ofthe switch matrix 200 to determine the appropriate allocation of eachswitch within the switch matrix 200 based on requests for data beingprocessed from subscriber destinations 109. In one embodiment, thebandwidth manager 161 monitors the bandwidth usage at every individualswitch including the manager switch 207, the audio switches 205, thecomputer network switches 203 and the video switches 201 of the switchmatrix 200 and at each gateway 139 of geographic serving area 107. Thebandwidth manager 161 may also monitor the bottom layer, or the switches201, to determine how much data is going to each subscriber destination109.

[0082] In an alternative embodiment, the switches 201, 203 and 205 arecoupled with redundant pathways as controlled by the bandwidth manager161. If a particular component switch within the switch matrix 200, forexample the video switch 201-1, reaches its bandwidth capacity, and ifanother video signal needs to be routed to the RF modem 121-2, ratherthan routing the additional video signal through the video switch 201-1,the bandwidth manager 161 re-routes the additional video signal throughanother video switch, such as the video switch 201-2, to the RF modem121-2. Any number of routing algorithms may be used to perform therouting function to avoid dropping of data packets at any particularswitch within the switch matrix 200.

[0083] It should be understood that different types of data could arriveat a single level within the switch matrix 200. The switch matrix 200does not necessarily have to be designed to accept a particular type ofdata at each level, but rather to accept a particular level of bandwidthof data at each level, where the highest bandwidth data is accepted atthe lowest level, an intermediate bandwidth data at an intermediatelevel, and a lower bandwidth data at a higher level. This serves to keepthe switch matrix 200 from being congested with data packets because thehighest bandwidth services only utilize the lower levels of the switchmatrix 200. It is further noted that while the switch matrix 200 hasbeen shown with four levels, any number of levels may be used toaccommodate different types, amounts and bandwidth of data. The incomingdata is routed through the switch matrix 200 according to actualbandwidth, actual usage at the particular switch and anticipated usage.

[0084]FIG. 3 is a block diagram of a communication network 300, which issimilar to the communication system 100 except that it employs adifferent allocation of the television broadcast spectrum and assignedchannels. In the communication network 300, broadcast televisionchannels are allocated to a particular frequency range of the overalltelevision broadcast spectrum. The remaining portion of the televisionbroadcast spectrum is utilized to assign data channels including anycombination of downstream and upstream channels. In an exemplaryembodiment in which the usable television broadcast spectrum is 5-860MHz, the frequency range of approximately 54 to 550 MHz is allocated tobroadcast television channels. The remaining spectrum, includingfrequency ranges 5 to 42 MHz and 550 to 860 MHz are allocated tosubscriber channels for dedicated bandwidth to each subscriberdestination 109. In a more particular embodiment, the frequency range550 to 860 MHz is allocated for downstream channels and the frequencyrange 5 to 42 MHz is allocated for upstream channels. The frequencyrange 42-54 MHz is the location of the diplex filter. It is understood,however, that the particular frequency ranges are exemplary only andthat any frequency allocation scheme may be employed depending upon thedesired configuration.

[0085] As shown in FIG. 3, the switch 119 communicates with therespective RF modems 121 in a similar manner previously described. TheRF modems 121 provide their outputs to respective inputs of a combiner303 of the point of distribution 103, where the combiner 303 operates ina similar manner as the combiner 125. In this embodiment, however, theoutput of a broadcast television server 301 is provided to another inputof the combiner 303. The broadcast television server 301 may be part ofthe source 101 or is a server within the point of distribution 103 thatreceives and forwards broadcast television information. The combiner 303is configured to receive and combine the broadcast televisioninformation from the broadcast television server 301 with the sourceinformation forwarded within assigned channels from the RF modems 121.In particular, the combiner 303 operates to overlay the broadcasttelevision channels with the channels of the RF modems 121 to develop acombined electronic signal provided to the optical transmitter 127. Theoptical transmitter 127 and the node 105 generally operate in a similarmanner as previously described, so that the combined overlaid spectrumis asserted onto the coaxial cable 137 to each of the subscriberdestinations 109.

[0086] Each subscriber destination 109 includes a corresponding gateway339 that is similar in operation to each gateway 139 and tuned to adownstream channel for the corresponding subscriber destination 109 toretrieve source information. The source information in the downstreamchannel, however, does not need to include any of the broadcasttelevision information that would otherwise be requested and sent to aset top box 141 in the communication system 100 via a corresponding RFchannel. Instead, for the communication network 300, each gateway 339receives the broadcast television information and additionally operatesas a splitter to split off the broadcast television information from thecombined signal and to forward the broadcast television information tothe set top box 141.

[0087] The broadcast television information may be in either analog ordigital format depending upon the particular configuration. If thebroadcast television information is in analog format, then an optionalcable or link 305-1 within the subscriber destination 109-1 illustratesan alternative embodiment in which the analog television signals splitfrom the assigned channels by the gateway 339-1 may be provided directlyto the television 143-1 rather than via the set top box 141-1. Fordigital broadcast television information, however, the set top box 141-1is utilized to convert the digital information to the appropriate analogformat for consumption by the television 143-1.

[0088] The communication network 300 may include the VID servers 111 forsending video-on-demand information to any one or more of the subscriberdestinations via corresponding channels in a similar manner aspreviously described. The video on demand information, however, mayconsume a significant amount of bandwidth thereby reducing the availablebandwidth to other subscriber devices, such as a corresponding computer147. In another alternative embodiment, a VOD and modulator server 313is provided that asserts its output to another input of the combiner303. The VOD server and modulator 313 operate to transmitvideo-on-demand information within the television broadcast informationfrequency range or within an adjacent channel. Although any downstreamchannel may be utilized for this purpose, each gateway 339 is configuredto receive and forward the video on demand information to thecorresponding set top box 141 for ultimate delivery to the correspondingtelevision 143. In this manner, a selected channel within or adjacent tothe television broadcast information is particularly convenient forreception by each gateway 339.

[0089]FIG. 8 is a block diagram of an exemplary embodiment of eachgateway 339 including a splitter 801 for filtering television broadcastinformation. The splitter 801 filters the television broadcastinformation from the broadcast television source 301 and provides thebroadcast information to the local set top box 141 or television 143 viaan optional interface module 707.

[0090] The communication system 300 is particularly applicable toconsumer-based networks in which it is desirable that cable televisionchannels be available directly from the coaxial cable 137 to thetelevision 143 and/or the set top box 141 via a splitter or the likewithout the need for further conversion. Also, any one or more of thesubscriber destinations 109 need not be equipped with a gateway 339 aslong as an appropriate splitter is used to filter the televisionbroadcast content from the packetized data channels. If a gateway 339 isnot provided at a subscriber destination 109, however, then it isdesirable to either prevent upstream communications from that subscriberdestination 109 or to otherwise restrict such upstream communications toreduce or eliminate the potential for broadcast information. Forexample, if a limited amount of upstream communications is desired, suchas video-on-demand requests or the like from a corresponding set top box141, then the set top box 141 is either equipped with a limited amountof transmit capability or gateway functions are incorporated into theset top box 141.

[0091]FIG. 4 is a block diagram of a communication network 400 that issimilar in function to either of the communication networks 100, 300previously described except employing an optical transmission pathway.The communication network 400 includes the switch 119, the bandwidthmanager 161 and the warp server 163. Each RF modem 121 is replaced by anoptical transceiver 421 (individually referenced as 421-X, again where“X” is a positive integer from 1 to N), where each optical transceiver421 includes an optical transmitter and an optical receiver (not shown).Each optical transceiver 421 communicates with the switch 119 in asimilar manner as the RF modems 121. Each optical transceiver 421converts data packets received from the switch 119 into an opticalsignal and provides the optical signal to a Wavelength DivisionMultiplexing (WDM) combiner 425. The WDM combiner 425 replaces thecombiner 125 and the optical transmitter 127. A WDM splitter 431replaces the splitter 131 and the optical receiver 129. Outside thepoint of distribution 103, the node 105 is replaced with a WDM selector405. The coaxial cable 137 is replaced with individual fiber opticcables 437 separately routed to each subscriber destination 109. Each ofthe subscriber destinations 109 includes an optical gateway 439(individually referenced as 439-X, again where “X” is a positive integerfrom 1 to N) that interfaces a corresponding fiber optic cable. Eachsubscriber destination 109 includes the same or similar subscriberdevices 141-151 previously described, where each optical gateway 439communicates to each of the subscriber devices 141-151 in a similarmanner. The communication network 400 provides a benefit of higherbandwidth capabilities as compared to HFC embodiments.

[0092] Each optical transceiver 421 converts forwarded packet data to anoptical signal, which is provided to a respective input of the WDMcombiner 425. The WDM combiner 425 optically multiplexes optical signalsfrom each of the optical transceivers 421 and provides a combinedoptical signal. The combined optical signal is transmitted by the WDMcombiner 425 via the optical cable 133 to the WDM selector 405. The WDMselector 405 receives and separates the combined optical signal into itsindividual optical signal components, and forwards separate opticalsignals over the appropriate optical fiber 437 to a corresponding one ofthe subscriber destinations 109. Each optical gateway 439 includes anoptical transceiver that receives and converts an optical signal to anelectrical signal for consumption by the various subscriber devices in asimilar manner previously described. Each optical gateway 439 performsimilar functions as the gateways 139, 339 previously describedemploying optical communications format.

[0093] Data packets originating from a subscriber destination 109 areconverted to optical signals by a respective gateway 439 and sent to theWDM selector 405 over a corresponding fiber optic cable 437. The fiberoptic cables 437 may comprise separate fiber optic cables including anupstream and a downstream cable. Each optical gateway 439 is associatedwith one of the optical transceivers 421, so that the communicationbetween the optical gateway 439 and the central location 403 ispoint-to-point along a particular assigned channel. The WDM selector 405receives and combines one or more optical signals, and sends a combinedoptical signal over the fiber optic cable 135 to the WDM splitter 431 atthe point of distribution 103. The WDM splitter 431 receives thecombined optical signal, splits the combined signal into its individualcomponents and forwards them over separate fiber optic cables 433 tocorresponding optical transceivers 421. Each optical transceiver 421receives a corresponding optical signal, converts it to data packets inan electric signal format, and forwards the subscriber data to theswitch 119.

[0094]FIG. 5 is a block diagram of a communication network 500 that issimilar to the communication network 400 except that the switch 119 isreplaced with an optical switch 501 and the optical transceivers 421 arereplaced with optical transceivers 521 that are configured tocommunicate with the optical switch 501 via optical node connections.The optical switch 501 communicates with source servers (not shown) orthe source 101 via optical signals, so that the servers are configuredto support optical communications. The optical switch 501 is coupled toa bandwidth manager 503 and a warp server 505, which are opticalversions of the bandwidth manager 161 and the warp server 163,respectively. Functional operation is similar.

[0095] Although the present invention has been described in detail, itshould be understood that various changes, substitutions and alterationscan be made hereto without departing from the spirit and scope of theinvention as described by the appended claims.

What is claimed is:
 1. A method of distributing information by a pointof distribution to subscribers via a communication network, comprising:dividing a television broadcast spectrum into a plurality of subscriberchannels, each subscriber channel having a deterministic bandwidth;allocating unshared bandwidth to each of a plurality of subscriberdestinations; assigning each of the subscriber destinations to asubscriber channel; forwarding source information to each subscriberdestination based on assigned subscriber channels; modulating sourceinformation for each subscriber channel; up converting modulated sourceinformation into a corresponding one of the subscriber channels;combining modulated information from each subscriber channel into acombined signal; and distributing the combined signal to the pluralityof subscriber destinations via the communication network.
 2. The methodof claim 1 , further comprising: dividing the television broadcastspectrum into an upstream portion and a downstream portion; andallocating each subscriber destination an unshared downstream bandwidthand an unshared upstream bandwidth.
 3. The method of claim 2 , whereineach subscriber channel includes a downstream subscriber channel in thedownstream portion and an upstream subscriber channel in the upstreamportion.
 4. The method of claim 1 , further comprising: subdividing atleast one subscriber channel into a plurality of bandwidth increments;and assigning multiple subscriber destinations to the at least onesubscriber channel, each of the multiple subscriber destinations beingallocated at least one of the bandwidth increments of the at least onesubscriber channel.
 5. The method of claim 1 , further comprising:receiving source information from a plurality of content servers in theform of data packets; and the forwarding comprising forwarding thereceived source information based on address information within the datapackets.
 6. The method of claim 1 , further comprising: tracking actualbandwidth usage of each subscriber destination.
 7. The method of claim 6, further comprising: monitoring source information by service typeprovided to a subscriber destination; and tracking bandwidth usage ofthe subscriber destination for each service type.
 8. The method of claim1 , wherein the dividing comprises dividing a substantial portion of thetelevision broadcast spectrum into the plurality of subscriber channels.9. The method of claim 1 , further comprising: receiving a request forvideo information from a subscriber destination via the communicationnetwork; receiving the requested video information in packetized format;forwarding the packetized video information to a subscriber channelassigned to the requesting subscriber destination.
 10. The method ofclaim 9 , wherein the video information is a broadcast televisionchannel.
 11. The method of claim 1 , further comprising: allocatingbroadcast television channels within a predetermined frequency range ofthe television broadcast spectrum; dividing the plurality of subscriberchannels into a remaining portion of the television broadcast spectrumoutside the predetermined frequency range allocated to the broadcasttelevision channels; and combining the broadcast television channelsinto the combined signal.
 12. The method of claim 11 , furthercomprising: allocating a first portion of the remaining portion of thetelevision broadcast spectrum to downstream subscriber channels; andallocating a second portion of the remaining portion of the televisionbroadcast spectrum to upstream subscriber channels.
 13. The method ofclaim 12 , wherein each subscriber channel comprises a respectivedownstream subscriber channel and a respective upstream subscriberchannel, each having a dedicated and unshared bandwidth.
 14. The methodof claim 1 , further comprising: converting the combined signal into anoptical signal; and transmitting the optical signal on an optical plantto an optical transceiver node.
 15. The method of claim 1 , furthercomprising: receiving a combined upstream signal from the communicationnetwork; splitting the combined upstream signal into multiple streams ofsubscriber information; providing each stream of subscriber informationto a corresponding one of a plurality of tuners, each tuner tuned to acorresponding subscriber channel; extracting, by each tuner, acorresponding return RF signal; demodulating a return RF signal intopacketized subscriber information; and forwarding the packetizedsubscriber information.
 16. The method of claim 15 , further comprising:the receiving comprising receiving an optical signal; and prior tosplitting the combined upstream signal, converting the optical signalinto the combined upstream signal.
 17. The method of claim 1 , furthercomprising: detecting a request by a subscriber destination forincreased bandwidth; and increasing the allocated unshared bandwidth tothe subscriber destination in accordance with the increased bandwidthrequest.
 18. The method of claim 1 , further comprising: detecting arequest by a subscriber destination for a service that would require agreater amount of bandwidth than currently allocated to the requestingsubscriber destination; and increasing the allocated unshared bandwidthto the requesting subscriber destination to handle the requestedservice.
 19. The method of claim 1 , further comprising: receiving aphysical address request from a subscriber destination; retrieving therequested physical address from a stored address database; andforwarding the retrieved physical address to the requesting subscriberdestination.
 20. The method of claim 19 , further comprising: if therequested physical address is not found, forwarding a broadcast addressresolution protocol request in an attempt to locate a device having therequested physical address.
 21. The method of claim 20 , furthercomprising detecting and halting abuse of address requests by asubscriber device.
 22. A method of communicating information between apoint of distribution and a plurality of subscriber destinations via ahybrid fiber coax (HFC) delivery plant, comprising: dividing atelevision broadcast spectrum into a plurality of subscriber channels,each subscriber channel having a deterministic bandwidth; assigning eachsubscriber destination to a subscriber channel; allocating unsharedbandwidth to each subscriber destination; forwarding, by the point ofdistribution, source information to each subscriber destination based onassigned subscriber channels; modulating, by the point of distribution,source information for each of the subscriber channels; up convertingmodulated source information into a corresponding one of the subscriberchannels; combining, by the point of distribution, modulated informationfrom each subscriber channel into a combined signal; is converting, bythe point of distribution, the combined signal into an optical signal;transmitting, by the point of distribution, the optical signal to anoptical transceiver node via an optical plant; converting, by theoptical transceiver node, the optical signal into a combined electricalsignal; and transmitting, by the optical transceiver node, the combinedelectrical signal via a coaxial cable to each of the plurality ofsubscriber destinations.
 23. The method of claim 22 , furthercomprising: extracting, by a gateway device at a subscriber destination,modulated information from an assigned channel of the combinedelectrical signal; demodulating, by the gateway device, sourceinformation from the extracted modulated information; and forwarding, bythe gateway device, demodulated source information to an addressedsubscriber device at the subscriber destination.
 24. The method of claim23 , prior to forwarding demodulated source information, furthercomprising: converting, by the gateway device, demodulated sourceinformation into a format appropriate for the addressed subscriberdevice.
 25. The method of claim 23 , further comprising: splittingbroadcast information from the combined electrical signal.
 26. Themethod of claim 25 , further comprising: converting retrieved broadcastinformation to appropriate format for a subscriber device.
 27. Themethod of claim 22 , further comprising: modulating, by a gateway deviceat a subscriber destination, subscriber information from a subscriberdevice; up converting, by the gateway device, the modulated subscriberinformation to a radio frequency (RF) signal into an assigned subscriberupstream channel; and transmitting, by the gateway device, thesubscriber RF signal to the optical transceiver node via the coaxialcable.
 28. The method of claim 27 , prior to modulating subscriberinformation, further comprising: converting the subscriber informationinto digital format.
 29. The method of claim 27 , further comprising:receiving, by the gateway device, a physical address request inbroadcast packet format; converting the physical address request to aunicast packet format; and forwarding the unicast physical addressrequest to an address resolution device at the point of distribution.30. The method of claim 22 , further comprising: tracking, by a gatewaydevice at a subscriber destination, actual bandwidth usage of thesubscriber destination; and forwarding bandwidth usage information to abandwidth manager at the point of distribution.
 31. The method of claim30 , further comprising: tracking, by the gateway device, bandwidthusage of the subscriber destination for each of a plurality of servicetypes; and forwarding bandwidth usage information for each of theservice types to the bandwidth manager.
 32. The method of claim 22 ,further comprising: sending, by a bandwidth manager at the point ofdistribution, a channel switch command to a gateway device at asubscriber destination; and switching, by the gateway device, from anassigned channel to another channel in response to the channel switchcommand.
 33. The method of claim 22 , further comprising: receiving, bythe optical transceiver node, a plurality of upstream subscriber RFsignals from the subscriber destinations; combining, by the opticaltransceiver node, the upstream subscriber RF signals into a combinedupstream signal; converting, by the optical transceiver node, thecombined upstream signal into an optical upstream signal; andtransmitting, by the optical transceiver node, the optical upstreamsignal via an optical plant to the point of distribution.
 34. Acommunication system for distributing information via a network to aplurality of subscriber destinations, comprising: a switch that forwardssource information for each subscriber destination to a correspondingone of a plurality of ports of the switch based on address information;a plurality of radio frequency (RF) modems, each RF modem coupled to oneof the plurality of ports of the switch, and each RF modem operable tomodulate and up convert information received from a respective switchport to an RF signal within a respective one of a plurality ofsubscriber channels of a television broadcast spectrum; each of theplurality of subscriber channels being assigned to one or more of thesubscriber destinations, each subscriber destination being assigned anunshared bandwidth allocation; a combiner, coupled to the RF modems,that combines modulated information from each RF modem into a combinedsignal; and a transmitter, coupled to the combiner, that transmits thecombined signal to the plurality of subscriber destinations via thenetwork.
 35. The communication system of claim 34 , further comprising:at least one source server, each coupled to respective ports of theswitch, that provides the source information.
 36. The communicationsystem of claim 35 , further comprising: the at least one source servercomprising a plurality of source servers including a video server, acomputer network server and a telephone network server.
 37. Thecommunication system of claim 35 , wherein the at least one sourceserver comprises an MPEG converter that receives and provides broadcastvideo content.
 38. The communication system of claim 34 , furthercomprising: the source information comprising data packets; and theswitch retrieving an address from data packets and forwarding the datapackets based on the address.
 39. The communication system of claim 38 ,wherein each address identifies one of the plurality of subscriberdestinations.
 40. The communication system of claim 39 , wherein eachaddress identifies a subscriber device of a subscriber destination. 41.The communication system of claim 34 , wherein the switch comprises anEthernet switch.
 42. The communication system of claim 34 , wherein theswitch comprises a matrix of switches.
 43. The communication system ofclaim 42 , wherein the switch matrix comprises arrays of switchesorganized as a pyramid configuration including a lowest level firstarray of switches and one or more higher level arrays of switches, eachfirst array switch coupled to a subset of the RF modems, and each switchof each higher level array coupled to a subset of switches of anadjacent lower level array.
 44. The communication system of claim 43 ,wherein the switch matrix further comprises: the first array forhandling a high level of bandwidth; a second array for handling a mediumlevel of bandwidth; and a third array for handling a low level ofbandwidth.
 45. The communication system of claim 44 , furthercomprising: the third array, coupled to a telephone network server, forhandling telephonic data; the second array, coupled to a computernetwork server, for handling telephonic and computer network data; andthe third array, coupled to a video server, for handling video,telephonic and computer network data.
 46. The communication system ofclaim 43 , further comprising: the switch matrix including a managerswitch coupled to at least one array switch; a bandwidth manager coupledto the manager switch; and an address resolution server coupled to themanager switch.
 47. The communication system of claim 46 , wherein themanager switch handles communications between subscriber destinations.48. The communication system of claim 42 , wherein the switch matrix isconfigured to operate significantly below its maximum bandwidth capacityto provide statistically starved capability.
 49. The communicationsystem of claim 34 , further comprising: the network including anoptical plant; and the transmitter comprising an optical transmitterthat converts a combined electrical signal to an optical signal and thattransmits the optical signal onto the optical plant.
 50. Thecommunication system of claim 49 , further comprising: an opticalreceiver, coupled to the optical plant, that converts an opticalupstream signal comprising subscriber information to a subscriberelectrical signal; a splitter, coupled to the optical receiver, thatprovides the subscriber electrical signal to a plurality of tuners; eachof the plurality of tuners extracting a corresponding subscriber RFsignal; and a plurality of demodulators, each demodulator demodulatingsubscriber information from a corresponding subscriber RF signal andforwarding the subscriber information to the switch.
 51. Thecommunication system of claim 34 , further comprising: a broadcasttelevision source that provides broadcast television information in apredetermined frequency range of the television broadcast spectrum; thesubscriber channels allocated into a remaining portion of the televisionbroadcast spectrum outside the predetermined frequency range; and thecombiner receiving and combining the broadcast television informationinto the combined signal.
 52. The communication system of claim 51 ,further comprising: a video on demand and modulator server that assertsvideo information; and the combiner receiving and combining the videoinformation into the combined signal.
 53. The communication system ofclaim 34 , further comprising: a bandwidth manager, coupled to theswitch, that allocates unshared bandwidth to each subscriberdestination.
 54. The communication system of claim 53 , furthercomprising: each subscriber channel comprising a plurality of bandwidthincrements; and the bandwidth manager allocating at least one bandwidthincrement to each subscriber destination.
 55. The communication systemof claim 53 , wherein the bandwidth manager detects a request by asubscriber destination for a service that requires a greater amount ofbandwidth than the subscriber destination is currently allocated, andwherein the bandwidth manager allocates additional unshared bandwidth tothe requesting subscriber destination.
 56. The communication system ofclaim 53 , wherein the bandwidth manager sends a channel switch commandto a subscriber destination to dynamically switch that subscriberdestination to another assigned channel.
 57. The communication system ofclaim 53 , wherein the bandwidth manager monitors bandwidth usage ofeach of the subscriber destinations.
 58. The communication system ofclaim 34 , further comprising: an address resolution server, coupled tothe switch, that stores an address database; and the address resolutionserver operative to respond to a physical address request by retrievingand forwarding the physical address based on a logical address.
 59. Acommunication system for distributing information via an opticalnetwork, comprising: an optical plant; a point of distribution,comprising: a multi-port switch that forwards source information foreach of a plurality of subscriber destinations to a corresponding port;a plurality of optical transceivers, each optical transceiver coupled toone of the plurality of ports of the switch to convert informationreceived from a respective port to a respective one of a plurality ofoptical source signals, and each optical transceiver assigned to one ormore subscriber destinations to allocated unshared bandwidth to assignedsubscriber destinations; and a wavelength division multiplexing (WDM)combiner that combines an optical source signal from each of theplurality of optical transceivers into a combined optical signal andthat transmits the combined signal onto the optical plant; a pluralityof fiber optic cables, each routed to a corresponding one of a pluralityof subscriber destinations; and a WDM selector, coupled to the opticalplant, that receives and separates the combined optical signal from theWDM combiner into its individual optical signal components, and thatforwards each separate optical signal over a corresponding one of theplurality of fiber optic cables to the subscriber destinations.
 60. Thecommunication system of claim 59 , wherein the switch comprises anoptical switch.
 61. The communication system of claim 59 , furthercomprising: a plurality of optical gateway devices, each located at arespective subscriber destination and coupled to a corresponding one ofthe plurality of fiber optic cables.
 62. The communication system ofclaim 59 , further comprising: the optical plant including an upstreamoptical plant; and the point of distribution including a WDM splittercoupled to the WDM selector via the upstream optical plant and coupledto each of the plurality of optical transceivers via a separate fiberoptic cable.
 63. A communication system for enabling communicationbetween a point of distribution and a plurality of subscriberdestinations via a hybrid fiber coax (HFC) network, comprising: anoptical plant; a point of distribution, comprising: a multi-port switchthat forwards source information for each subscriber destination to acorresponding port of the switch based on address information; aplurality of radio frequency (RF) modems, each RF modem coupled to aport of the switch, and each RF modem operable to modulate and convertinformation received from a respective switch port to an RF signalwithin a respective one of a plurality of subscriber channels of atelevision broadcast spectrum; each of the plurality of subscriberchannels having a deterministic bandwidth and assigned to one or more ofthe subscriber destinations, each subscriber destination being assignedan unshared bandwidth allocation; a combiner that combines modulatedinformation from each RF modem into a combined signal; and atransmitter, coupled to the combiner and the optical plant, thatconverts the combined signal to an optical signal and that transmits theoptical signal via the optical plant; a coaxial cable distributed to aplurality of subscriber destinations; and an optical transceiver node,coupled to the optical plant and the coaxial cable, that converts theoptical signal to an electrical signal and that transmits the electricalsignal to subscriber destinations via the coaxial cable.
 64. Thecommunication system of claim 63 , further comprising: a plurality ofgateway devices, each located at a respective subscriber destination andcoupled to the coaxial cable, each comprising: a tuner, for coupling tothe coaxial cable, that is tuned to an assigned subscriber channel toextract modulated information from the electrical signal; and ademodulator, coupled to the tuner, that demodulates the extractedmodulated information into source information.
 65. The communicationsystem of claim 64 , wherein the tuner is dynamically programmable toswitch to at least one other of the subscriber channels.
 66. Thecommunication system of claim 64 , wherein the tuner is dynamicallyprogrammable to tune to multiple subscriber channels.
 67. Thecommunication system of claim 64 , wherein each gateway device furthercomprises: a gateway switch, coupled to the demodulator, that forwardssource information to an addressed one of a plurality of subscriberdevices.
 68. The communication system of claim 67 , wherein each gatewaydevice further comprises: a plurality of converters, each coupled to thegateway switch, that converts source information to an appropriateformat for a corresponding subscriber device.
 69. The communicationsystem of claim 68 , further comprising: a set top box coupled to thegateway device; and the gateway device including a video converter thatconverts source information into video data that is forwarded to the settop box.
 70. The communication system of claim 68 , further comprising:a telephone coupled to the gateway device; and the gateway deviceincluding an audio converter that converts digital audio data from thesource information into telephone analog signals that are provided tothe telephone.
 71. The communication system of claim 67 , wherein eachgateway device further comprises: management and control logic, coupledto the gateway switch, that monitors bandwidth usage of a correspondingsubscriber destination and that forwards bandwidth usage information tothe point of distribution.
 72. The communication system of claim 71 ,wherein the management and control logic monitors bandwidth usage foreach of one or more service types and reports service type bandwidthusage to the point of distribution.
 73. The communication system ofclaim 71 , wherein the management and control logic receives a physicaladdress request in broadcast format from a local subscriber device,converts the request to unicast format, and forwards the unicastphysical address request to the point of distribution.
 74. Thecommunication system of claim 64 , wherein each gateway device furthercomprises: a splitter, for coupling to the coaxial cable, that splitsbroadcast content from the electrical signal.
 75. The communicationsystem of claim 74 , wherein each gateway device farther comprises: avideo converter, coupled to the splitter, that converts digital videoinformation into analog format.
 76. The communication system of claim 64, wherein each of the plurality of gateway devices further comprises: amodulator that modulates subscriber information from a subscriberdevice; and an up converter, coupled to the modulator and the coaxialcable, that converts modulated subscriber information to a radiofrequency (RF) signal into an assigned subscriber upstream channel andthat transmits the upstream RF signal to the optical transceiver nodevia the coaxial cable.
 77. The communication system of claim 76 ,wherein each of the plurality of gateway devices farther comprises: aconverter, coupled to the modulator and for coupling to a subscriberdevice, that converts the subscriber information into digital format.78. The communication system of claim 76 , further comprising: theoptical transceiver node including an optical converter that converts aplurality of upstream RF signals from the coaxial cable into an upstreamoptical signal and that transmits the upstream optical signal to thepoint of distribution via the optical plant.